Basically I need to read certain cell values out of a batch of excel files in a certain directory, and write to another excel file. For example add up all values from B3 in a directory of files and write to another one.

Is there a nice API to do this, or can excel do this already, or is there something out there that can do this.

The files will be changed once a week, and once a week i wanted to be able to run this and create a new file from it.

Any ideas on how to attack this would be great. C++ and C# is preffered.